1. Field of the Invention
This invention relates to monitoring the temperature of rotating devices used in industrial applications such as paper milling, textiles, food processing, pharmaceuticals, chemicals, power generation, motors, generators, bearings, engines and the like.
2. Description of the Background Art
In paper milling, textiles, food processing, pharmaceuticals, chemicals and power generation industries the monitoring of temperature is critical. During one or more of the steps involved in the manufacturing process; the product or an ingredient of the product is rotated. The real time measurement of temperatures during this rotation process is accomplished, if at all, by unreliable and inaccurate equipment.
An example of a rotating device is a dryer drum used by the paper milling industry. Another example of a rotating device is the auger used by the food industry. The food processing industry uses a rotating device known as a rotating retort. Yet another example of a rotating device are turbines used in the generation of electricity by the power industry.
A typical application of a rotating device can be demonstrated and more fully understood by examining the use of a rotating drum in the production of paper or textiles as employed by these industries in the manufacture of their respective products.
In the processing of paper or textiles, one of the steps involved is the removal of moisture from the product. The textile or paper materials are typically dried by passing them over the surfaces of a series of cylindrical structures called drums. Because the production rate and the quality of the product are affected by the temperature of the drums, maintaining proper drum temperature is an important aspect of the production process.
One technique currently used for monitoring dryer drum temperatures involves the use of a handheld infrared temperature sensor gun. Temperature readings can be taken by pointing the sensor gun at an exposed surface of a drum. However, such temperature readings must be taken manually and are strongly influenced by the emissivity of the drum. Because drum emissivity can vary depending on the surface condition of the drum (i.e., whether the drum is painted, rusted from exposure to water, shiny, etc.), temperature readings taken using handheld infrared temperature sensors can be grossly inaccurate.
Another technique for monitoring drum temperatures involves using a handheld rubbing-contact temperature sensor. Rubbing-contact temperature sensors typically have wheeled carriages that are placed in rubbing contact with an exposed surface of the rotating drum. Because rubbing-contact sensors are placed in proximity to the moving surfaces of the paper making machinery, the use of such sensors is not without risk to the operator taking the temperature measurement. In addition, typical rubbing-contact sensors are speed rated, so that a given sensor can only be used to make temperature measurements if the drum is rotating below a particular speed.
Still another technique for monitoring drum temperatures involves calculating the drum temperature based on known parameters, such as the pressure of the saturated and supersaturated steam used to heat the interior of the drum. The thickness of the water condensate layer built upon on the inner drum surface, the rate of evaporation on the exterior of the drum, the structure of the drum (i.e., whether the drum has any raised surfaces), etc. can adversely effect these calculations. The results of this type of heat flow analysis tend to be inaccurate, because it is not possible to measure or determine all of the parameters that influence the drum temperature or to precisely gauge the interplay between the various measured parameters and the drum temperature.
It is therefore an object of the present invention to provide an improved technique for monitoring the temperature of rotating devices used in industrial applications such as paper milling, textiles, food processing, pharmaceuticals, chemicals, power generation, motors, generators, bearings, engines and the like.
In response to the realized inadequacies of these systems for monitoring dryer drum temperatures, it became clear that there is a need for a reliable and accurate system for monitoring the temperature of rotating devices used in industrial applications such as paper milling, textiles, food processing, pharmaceuticals, chemicals, power generation, motors, generators, bearings, engines and the like.
This improved system for monitoring the temperature of a rotating device must provide an accurate temperature reading and control in order to maximize the quality and productivity of the processing steps in a manufacturing process. Inasmuch as the art consists of various types of systems for monitoring temperatures, it can be appreciated that there is a continuing need for and interest in improvements to systems for monitoring the temperature of a rotating device, and in this respect, the present invention addresses these needs and interests.
Therefore, the principal object of this invention is to provide an improved system for monitoring the temperature of a rotating device which overcomes the aforementioned inadequacies of the prior art and provides an improvement which is a significant contribution to the advancement of the industrial arts such as paper milling, textiles, food processing, pharmaceuticals, chemicals, power generation, motors, generators, bearings, engines and the like.
Another object of this invention is to provide an improved system for monitoring the temperature of a rotating device which has all the advantages and none of the disadvantages of the earlier systems for monitoring the temperature of a rotating device.
Yet still another object of the present invention is to provide an improved system for monitoring the temperature of a rotating device such that the rotational speed of the rotating device does not affect the accuracy of measured temperature.
Still another object of the present invention is to provide an improved system for monitoring the temperature of a rotating device such that the placement of an antenna is insensitive to minute changes in environment or location for the detection of a signal generated by a sensor on a rotating device.
Still another object is to provide an improved system for monitoring the temperature of a rotating device where the gathering of data is not affected by the infrequency of data collection.
Yet another object is to provide an improved system for monitoring the temperature of a rotating device where the accuracy of the temperature measured will not be degraded by changes in the frequency or amplitude of the signal generated by the sensor on the rotating device.
Still a further object of the present invention is to provide an improved system for monitoring the temperature of a rotating device where the sensor transmits at low frequencies.
Another object of this invention is to provide an improved system for monitoring the temperature of a rotating device employing a magnetic link to detect the signal sent by the sensor to the antenna.
Yet another object is to provide an improved system for monitoring the temperature of a rotating device where transmitted information is obtained in short time periods asynchronously.
Yet another object is to provide an improved system for monitoring the temperature of a rotating device where a binary signal is provided to validate the information received in order to calculate an accurate temperature.
A further object is to provide an improved system for monitoring the temperature of a rotating device comprising: a sensing means; an antenna means; a receiver means; an amplification means; a first splitting means; a phase lock loop circuit; a second splitting means; an amplitude modulation discriminator means; a comparing device; a control line signal; a counter logic circuit; a time based signal; a synchronized signal; and a microprocessor.
The foregoing has outlined some of the pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a more comprehensive understanding of the invention may be obtained by referring to the summary of the invention, and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the acompanying drawings.